Release v0.19.0

What's Changed

• fix(pp-dev): WebSocket per-client responses and sub-path template variable loading by @sergak01 in #168
• feat(next): dev panel and template sync for Next.js apps by @sergak01 in #171
• fix: address CodeRabbit review findings (distZip gate, socket leak, send overload, outbox cap) by @sergak01 in #173
• 🚀 Promote develop to main (0.19.0-beta.1 — Next.js dev panel + audit fixes) by @sergak01 in #172

Full Changelog: v0.18.3...v0.19.0